Welded butt joints, typical of those used in the flanges of steel plate girders, were welded by electroslag and submerged arc processes in ASTM A36 and A588 steel plates. The electroslag weldments were made by the consumable guide method using both the water cooled and non-cooled retaining shoes. Complete metallurgical studies were done on the weldments to define and document the various weld metal and heat-affected zones that were present. Chemical compositions of the various weldment zones are presented and discussed. Deficiencies were discovered in the alloy composition of some of the weldments in A588 steel that were approved for use in a bare, unpainted exposure. Control of weld metal chemistry is seen to be very difficult in an electroslag weldment. Tensile tests on the various weldments regeal significant nonhomogeneous and anisotropic behaviors in the electroslag weld metal. Three series of Charpy V-notch impact evaluations were conducted on the weldments. The 1st series evaluated the performance of all the weld metal zones, the heat affected zones, and the base metal at a test temperature of 0 F. These tests revealed the nonhomogeneous nature of the impact toughness in electroslag weld metal and a failure to meet acceptance criteria by some of the weldments. The 2nd series involved impact testing over the temperature range of minus 40 to plus 40 F and revealed the temperature-transition characteristics of the weldment zones. The 3rd series of Charpy tests revealed the highly anisotropic nature of the impact toughness of the electroslag weld metal zones. Fatigue crack initiation tests were conducted on small tensile specimens taken from the weldments with crack starter notches machined in them. These tests revealed that the submerged arc weld metal has a significatly longer crack initiation life than the electroslag weld metal and that in some cases the electroslag weld metal was inferior to the base metal. Recommended changes in specifications are also included.